Safety device for presses.



W. COTTRELL.'

SAFETY DEVICE FOR PRESSES.

APPLICATION `FILED MAY 23.1914.

Patented 53.1.16,11917.

3 SHEETS-SHEET l.

W. COTTRELL.

` Patented Jan. 16, 1917.

3 SHEETS-SHEET 2.

W. COTTRELL.

SAFETY DEVICE FOR PRESSES.

APPLICATION FILED MAY 2.3. I9I4.

MMIII!!! m/IW WM Patented Jan. 16, 1917.

3 SHEES-SHEET 3.

fell

WED ,STATES @PATENT oEEIsE.

WILLIAM CoTTnEL'L, OE CHICAGO, ILLINOIS, AssIGNOE 'To BENJAMIN ELECTRICMANU- EACTUEING COMPANY, OE CHICAGO, ILLINOIS, -A CORPORATION OEILLINOIS.

SAFETY :DEVICE Eon PRESSES,

pecicaton of Letters Patent.

Applicaties mea may 2a, 1914. serial No. 840,456.

My invention relates to improvements in safety devlces for presses ofvarlous characters and particularly for punch presses.

My invention is particularly designed for the protection of an-operatorworking on a stamping press which press uses a stripper plate, one ofthe objects being to providev means for preventing the operator from\,getting his hands in a dangerous position during the operation ofthepress, and for preventing the press from being operated when thestripper plate of the press is raised for the `purpose of inspection,changing dies, etc.

I have illustrated in the accompanying drawings one embodiment of myinvention, in which drawings--\y Figure 1 is a side elevation of theright hand side of so much of the press as is necessary to disclose myinvention; Fig. 2 is a side elevation of the left hand. side of thepress; F ig; 3 is a front elevation of the press; and Fig. 4 kis adetail showing the tripping and locking mechanism of the press.

Referring to the drawings, the press 1 is of anyof the well-knownconstructions and is provided ywith the usual trip clutch 2 which isadapted to be operated by a tripping mechanism of 'any well-known construction. That illustrated in the drawings comprises a bell crank leverpivoted to a bracket 3 and having one arm 4 thereof adapted to lie inthe path of the clutch mechanism to hold this mechanism out of trippedposition. The opposite arm 5 of the crank lever is connected by asuitable rod 6 with a pivoted arm 7 and held in its raised ornon-operative position by a coiled spring 8. This arm 7 is alsoconnected by a rod 9 with a suitable foot or hand lever (not ping,mechanism thus in a non-,operated position, I provide a coiledcompression spring e 10 for holdingthe bellcrank lever or latch above@described in a non-operated position. This mechanism above 'describedis-,of the usual construction, and, in operation, wh`en it is desired totrip the press, pressure is applied to the hand or foot lever therebythrowing the arm 4: out of the path of the projection on the trippingclutch permitting this clutch to operate and thereby causing the punchor ram ofthe press to descend. The press shown in the accompanying 1drawings is provided with a' stripper'plate 11 through which the punchof the press is adapted to operate' and beneath which the material isadapted to be fed. This stripper plate extends over the die 12 and ismounted upon the lower ends of a pair of vertical posts 13, onelarranged on each side of the press and operating in suitable guides 14formed in castings 15` boltedor otherwise secured on the stationaryframe of the press` Suitable sockets 16 are provided on thel Patented Jan. 16,

of various sizes the position of the stripper plate is a-djusted bymeans of pins 17 which engage any one of `a plurality` of small holes`-18 formed in theposts 13, the pins 17 passing through a collar 19, onthe posts, which is attached to the raising mechanism as hereinafterdescribed. The stripper plate is adapted to remain in its lowermostposition during the,operation of the press, and, in order to prevent theoperator-from getting his fingers in a dangerous position during thereciprocation of the ram or punch of the press, I mount on this stripperplate a guard 20, which extends across Athe front of the press and`around on two sides of the press. 'Ihis guard being of suliicient heightand extending far enough around on each side to completely inclose themovable operatingin a dangerous position during the movement of the ramof the press.

In the operation of a press of thischaracter it frequently becomesessential that the stripper plate be raised for the purpose ofinspecting the dies or inserting new dies and` the like. To raise thestripper plate, and, atthe same time, prevent'the press from beingtripped-while the stripper and with it ted lines in the guard are beingraised, I provide ra raising and locking mechanism. To the collar 19 onthe right hand rod 13 I pivot a link 21, the upper end of which ispivotally connected to the lower'end of a second link 22. The upper endof this link 22 is pivoted to the side frame as at 23 and projectingabove the pivoted pointl is a stop portion 24 ladapted, when the linksare operated, to be thrown into the path of the bellcrank lever arm 4.The link 22 is provided at its lower end with a forwardly extendingportion/25 to which is secured the handle bar 26'. The opposite end ofthis handle bar is connected to a similarly shaped bell crank lever 27mounted on theopposite side of the press. This lever is connected by alink similar to the link 21 which, in turn, ris connected to the collar19 on the upright 13 on the left hand side of the press'. Thisarrangement provides means whereby when the handle bar is raised, thetreadle bein first released, as shown in dotig. 1,'the stripper plate 11and with it the guard 20 are raised to permit access to the dies. At thesame time that the handle 25 is raised it rocks the link 22 on itspivot, throwing the stop projection 24 in the path of the bell crank arm4 so that this bell crank arm cannot be moved, thereby preventing thearm from being operated by the foot lever to trip the press It sometimeshappens that vwhen the tripping mechanism is thrown into an inoperativeposition to thereby permit the clutch to release so that the, press willnot operate, the clutch parts stick, and in spite of the fact that thepress is supposed to have been dis-l connected continues to operate.Therefore in order to prevent accidents of this kind happening when theguard 20 is in a raised position andthe operator exposed to danger, Iprovide means to absolutely lock the press from operatingwhen the guardis raised. At the same time, this means provides a mechanism whereby theguard cannot be raised as long as the ram of the press is on itsdownward movement. On the left hand side of the press, and on the crankshaft of the ram, I provide a cam wheel 28 provided with a cam face 29`and a stop face 30. This wheel is keyed on the crank shaft of the pressram and the cam face 29 occupies the same relative position as the crankof the crank shaft.

Pivotally mounted on the side of the press is a stop dog 31 which isconnected by a link 32 with the arm 27 on the left hand side ofthe'press, so that, when the arm 27 is raised,

the stop dog 31 will be thrown into the pathr of the stop face 30 on thecam member, thereby absolutely preventing the rotation of thegaged bythe dog 31. If the ram has started on its downward movement the cam face29 will be in the path of the do 31 and as this dog is connected to thearm 2 it is apparent that the arm and with it the guard and stripperplate cannot be raised until the cam face has. moved past the dog. Bythe time the cam face has moved past the dog the ram will' have startedin its upward movement and all danger to the operator will have passed.

It will thus be seen that by the above I provide a means which not onlyserves to absolutely lock the press against operation when the guard israised, but also serves to prevent the guard from being raised as longas the ram of the press is moving in a downward or dangerous path.

In order that the stripper plate and guard may be held in a raisedposition when once raised, the treadle having been rst released7 so thatthe operator may have bothV hands free to attend to the changing of thedieser performing other necessary duties, I provide a catch 33 which ispivoted to one side of the frame and is forced to an engaging positionby the spring 34. The notch 35 of this catch is adapted to engage undera laterally extending pin 36 on one of the rods 13 when the rod israised, and thereby hold the rod and with it the stripper plate in araised position. As soon as it is desired to start the press again theoperator may move the catch out offengagement with the pin by the handle37, when the stripper` plate is lowered to assume its proper operatingposition, it being, of course, understood that the guard 4drops with thestripper plate and the operator is thereby prevented from inserting hishands in a dangerous position in the press. While lI have shown anddescribed one embodimentof my invention in the accompanying drawings, itwill be understood that various modifications and changes may be. madetherein Without departing from the spirit of the invention as set forthin the accompanying claims. f

Having thus described my invention what I claim as new and desire tosecure by Letters Patent, is

l. In a device of the character described,

the combination with a tripping mechanism,

the combination with a press, of tripping mechanism therefor, a stripperfor said press, a guard carried by sald stripper for preventingy theoperator from getting his hands in a dangerous position as long as saidstripper` is in operative position, means mechanism forsaid press, astrlpper for 4 said press, means for raising said stripper, and a stopmoved in the path of the movable member of the tripping mechanism of thepress when said stripper is raised'to prevent the pressfrom beingtripped as'long as the stripper is in a raised position.

. 4. In a device of the character described, the combination with apress, of a tripping mechanisml for said press, a Vstripper for said'press,"and an inter-lock between saidv stripper and tripping mechanismfor preventing the tripping of -the press when the stripper is moved toan inoperative position.

5. In a device of the character described,y the combination with apress, of a normally stationary stripper for said press, a trip,- pingmechanism for the press, means for moving said stripper, and means forlocking said tripping mechanism against operation when 'said stripper ismoved.

6. In a device of the character described, the combination With a press,of a tripping mechanism therefor, a relatively stationary strippingplate through which the movable punch of the press passes in operation,means for raising said plate to permit access to the dies of the press,and means op-y erated by the raising of the plate to prevent thetripping of the press when the plate is raised.

7. In a device of the character described, the combination witha press,of a tripping mechanism for said press, a stripper for said press,`means for preventingthe tripping of the press when the stripperisraised, and means for preventing the raising of said stripperwhen theram of the press is moving in its downward path..

8. In a device of the character described,

l the combination with a press, of a stripper therefor, means forraising said stripper to permit access to the dies lof the press, andmeans for locking said stripper in-itslowered position as long as theram of the press is moving in a downward path.

9. In a device of the character described, the combination with a press,of'aguard therefor, means for locking the tripping mechanism of thepress against operation when said guard is raised, and; means forpreventing movement of` the ram of the press when said guard is'raised.

10. In a device of the character described, the hcombination with apress, of a tripping mechanism therefor,'a guard for preventing theoperator from placing his hands in a dangerous position during theoperation of the press,V means for locking the tripping `stop memberactuated by said 'movable the operatorv from inserting his hands in adangerous positiondiiring the operation of the press, means for raisingsaid guard to permit access to the dies of the press, means operated bythe raising of the guard for preventing the operating of said trippingmechanism when the guard is raised, and

of the press when said guard is raised.

12. In a device of the character described,

the combination with a press, of a tripping mechanism therefor,a guardfor preventing the operator from inserting his hands lin a dangerousposition during the operation ofthe press, means ,for locking thetripping mechanism against operation when 'the guard is raised to permitaccess to the dies of the press, and means for preventing movement ofthe ram of the'press when the guard is raised and for preventing theguard from being raised when 'the ram of thepress is moving in itsdownward path.

13. In a device of the class described, the combination with a presshaving a ram, and a crank shaft for driving said ram, of a guard, andmeans exerting force on said crank shaft for preventing movement thereofcontrolled by said guard.-

14. In a device of the class described, the

'combination with a press having a ram, and

a crank shaft for driving said` ram, of a guard, and means exertingVforce on said crank shaft for preventing movement thereof controlled bysaid. guard, said means including a stop member secured to said shaft.

15. In a device of the class described, the

' combination with a press having a ram, and

a crank shaft for driving said ram, of a guard, means exerting 'force onsaid crank shaft for preventing movement thereofv con- `means forpreventing movement of the ram trolled by said guard, said meansincluding a stop member secured to said shaft, and a ard and yinto 'thepath of said rst stop member. v

16. In a device of the ,class described, the combination` with a press'having'a ram, and a crank shaft for driving said ram, of a guard andmeans for holding the ard in guarding position controlled by said. crankshaft, and means exerting a force on said crank shaft for preventingmovement thereof controlled by said guard.

17; In a device of the class described, the combination'with a presshaving'a ram, and a crankshaft for driving said ram, of a guard andmeans for holding the guard in guarding position controlled by saidcrank scribed my name in the presence of two witshafilz, zlnrtlieansexerting a foroe on `said nesses. cran s a or preventing movementthereof, said last two means including a member, WILLIAM COTTRELL' 5secured to said shaft having a cam surface Witnesses:

and a stop. W. PERRY HALEY, In witness whereof, I have hereunto sub-ANNE SOLOMON.

